1. Field of the Invention
The present invention relates to a magnetic memory cell and a magnetic random access memory each on which a magnetoresistive device is mounted.
2. Description of the Related Art
An attempt has been made on the application of a tunnel magnetoresistive device with a large output to recording/reproducing cells in a high density magnetic memory. For such tunnel magnetoresistive device, a tunnel magnetoresistive device including an insulator for which an Al oxide is used and a tunnel magnetoresistive device including an insulating film for which magnesium oxide is used, have been disclosed (T. Miyazaki and N. Tezuka, J. Magn. Magn. Mater. 139, L231 (1995); and S. Yuasa, et al., Nature Material 3, 868(2004)). A conventional nonvolatile magnetic memory is formed of memory cells each in which a tunnel magnetoresistive device is formed on a MOSFET (metal oxide semiconductor field effect transistor). The conventional type of nonvolatile magnetic memory employs a scheme in which: a MOSFET is used as a switching element in each memory cell; information is written in the memory cell by rotating the magnetization direction of the tunnel magnetoresistive device by use of a current-induced spatial magnetic field generated by energizing the bit line and the word line; and the information is read from the memory cell by use of an output voltage from the tunnel magnetoresistive device. In addition to the scheme of the magnetization rotation by use of the current-induced spatial magnetic field, there is also employed what is termed as a spin transfer torque magnetization switching scheme in which the magnetization direction of a magnetoresistive device is switched by applying a current to the magnetoresistive device directly. This technique is disclosed, for example, in U.S. Pat. No. 5,695,864 and in Japanese Patent Application Publication No. 2002-305337.